Abstract/Summary Antifreeze proteins (AFPs) are natural antifreeze molecules that have been found in many organisms including fish, insects, plants, bacteria, and fungi. AFPs exhibit great structural diversity, while they are all characterized by their unique ability to depress the freezing point of water without affecting the melting point apparently. The resulting difference between the melting point and the freezing point, referred to as thermal hysteresis (TH), is generally used as a measure of the antifreeze activities of AFPs. AFPs and co-solutes in body-fluids of cold-adapted organisms are responsible for survival in cold environments. Certain small molecule and protein co-solutes can further enhance the antifreeze activity of AFPs, referred to as enhancers, by binding to AFP through ionic interactions, hydrogen bonding, and/or hydrophobic interactions. AFP-based antifreeze systems (AFP plus enhancer) are much more effective and their uses are more environmentally friendly in comparison to conventional antifreezes, making them intriguing alternatives to conventional antifreezes in particular in biomedical fields. The proposed research will investigate the little known AFP- protein systems through determining the cryoprotective effect of an AFP on other proteins as well as the effect of these proteins on the antifreeze activity of the AFP using combined biochemical and biophysical methods. The information on such interplay in the AFP-protein systems would not only further our understanding of biological antifreeze system in cold-adapted organisms, but also lead to the development of effective protective systems for long-term preservation of important biologics in biomedical applications.

The proposed work provides a detailed understanding on the interplay of the partners in the systems of antifreeze proteins and other proteins. Antifreeze protein based systems are intriguing alternatives to conventional antifreezes in biomedical fields. This study would help unravel survival strategy in cold-adapted organisms and lead to rational development of highly efficient cold preservation/antifreeze systems for long-term preservation of important biologics for various biomedical applications.